[R] Cross Validation in rpart

[R Help]

Hello All,
     I'm writing a custom rpart function, and I'm wondering about
cross-validation.  Specifically, why isn't my splitting function being
called more often with the xval increased?  One would expect that,
with xval=10 compared to xval=1, that the prior would call the
splitting function more than the other, but they both produce the
exact same thing.  Is there something I'm missing about the
cross-validation process for rpart?

Thanks,
Sam Stewart